Controller support for VrShell

chrome/browser/android/vr_shell/vr_controller.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/android/vr_shell/vr_controller.h"
+
+#include <android/log.h>
+
+#include <cmath>
+
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+using blink::WebInputEvent;
+
+namespace vr_shell {
+
+namespace {
+
+const GestureScroll kDefaultGestureScroll = {{0, 0}, 0, {0, 0}};
+const GestureButtonsChange kDefaultGestureButtonsChange = {{0, 0}, 0, 0};
+const GestureAngularMove kDefaultGestureAngularMove = {{0, 0, 0}, 0};
+
+constexpr float kDisplacementScaleFactor = 800.0f;
+
+// A slop represents a small rectangular region around the first touch point of
+// a gesture.
+// If the user does not move outside of the slop, no gesture is detected.
+// Gestures start to be detected when the user moves outside of the slop.
+// Vertical distance from the border to the center of slop.
+constexpr float kSlopVertical = 0.165f;
+
+// Horizontal distance from the border to the center of slop.
+constexpr float kSlopHorizontal = 0.125f;
+
+// Minimum distance needed in at least one direction to call two vectors
+// not equal.
+constexpr float kDelta = 1.0e-7f;
+
+class Vector {
+ public:
+  static inline void ClampTouchpadPosition(gvr::Vec2f* position) {
+    position->x = std::min(std::max(0.0f, position->x), 1.0f);
+    position->y = std::min(std::max(0.0f, position->y), 1.0f);
+  }
+
+  static inline void VectSetZero(gvr::Vec2f* v) {
+    v->x = 0;
+    v->y = 0;
+  }
+
+  static inline gvr::Vec2f VectSubtract(gvr::Vec2f v1, gvr::Vec2f v2) {
+    gvr::Vec2f result;
+    result.x = v1.x - v2.x;
+    result.y = v1.y - v2.y;
+    return result;
+  }
+
+  static inline bool VectEqual(const gvr::Vec2f v1, const gvr::Vec2f v2) {
+    return (std::abs(v1.x - v2.x) < kDelta) && (std::abs(v1.y - v2.y) < kDelta);
+  }
+};  // Vector
+
+}  // namespace
+
+VrController::VrController(gvr_context* vr_context) {
+  Initialize(vr_context);
+  Reset();
+}
+
+VrController::~VrController() {}
+
+void VrController::OnResume() {
+  if (controller_api_)
+    controller_api_->Resume();
+}
+
+void VrController::OnPause() {
+  if (controller_api_)
+    controller_api_->Pause();
+}
+
+bool VrController::IsTouching() {
+  return controller_state_.IsTouching();
+}
+
+float VrController::TouchPosX() {
+  return controller_state_.GetTouchPos().x;
+}
+
+float VrController::TouchPosY() {
+  return controller_state_.GetTouchPos().y;
+}
+
+const gvr::Quatf VrController::Orientation() {
+  return controller_state_.GetOrientation();
+}
+
+bool VrController::IsTouchDown() {
+  return controller_state_.GetTouchDown();
+}
+
+bool VrController::IsTouchUp() {
+  return controller_state_.GetTouchUp();
+}
+
+bool VrController::IsButtonDown(const int32_t button) {
+  return controller_state_.GetButtonDown(button);
+}
+
+bool VrController::IsButtonUp(const int32_t button) {
+  return controller_state_.GetButtonUp(button);
+}
+
+bool VrController::IsConnected() {
+  return controller_state_.GetConnectionState() == gvr::kControllerConnected;
+}
+
+void VrController::UpdateState() {
+  const int32_t old_status = controller_state_.GetApiStatus();
+  const int32_t old_connection_state = controller_state_.GetConnectionState();
+  // Read current controller state.
+  controller_state_.Update(*controller_api_);
+  // Print new API status and connection state, if they changed.
+  if (controller_state_.GetApiStatus() != old_status ||
+      controller_state_.GetConnectionState() != old_connection_state) {
+    VLOG(1) << "Controller Connection status: "
+            << gvr_controller_connection_state_to_string(
+                   controller_state_.GetConnectionState());
+  }
+}
+
+void VrController::Update(bool touch_up,
+                          bool touch_down,
+                          bool is_touching,
+                          const gvr::Vec2f position,
+                          int64_t timestamp) {
+  CHECK(touch_info_ != nullptr) << "touch_info_ not initialized properly.";
+  touch_info_->touch_up = touch_up;
+  touch_info_->touch_down = touch_down;
+  touch_info_->is_touching = is_touching;
+  touch_info_->touch_point.position = position;
+  Vector::ClampTouchpadPosition(&touch_info_->touch_point.position);
+  touch_info_->touch_point.timestamp = timestamp;
+
+  UpdateGestureFromTouchInfo();
+}
+
+void VrController::Initialize(gvr_context* gvr_context) {
+  CHECK(gvr_context != nullptr) << "invalid gvr_context";
+  controller_api_.reset(new gvr::ControllerApi);
+  int32_t options = gvr::ControllerApi::DefaultOptions();
+
+  // Enable non-default options, if you need them:
+  // options |= GVR_CONTROLLER_ENABLE_GYRO;
+  CHECK(controller_api_->Init(options, gvr_context));
+  controller_api_->Resume();
+}
+
+VrGesture VrController::DetectGesture() {
+  if (controller_state_.GetConnectionState() == gvr::kControllerConnected) {
+    gvr::Vec2f position;
+    position.x = TouchPosX();
+    position.y = TouchPosY();
+    Update(IsTouchUp(), IsTouchDown(), IsTouching(), position,
+           gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos);
+    if (GetGestureListSize() > 0 &&
+        (GetGesturePtr(0)->type == WebInputEvent::GestureScrollBegin ||
+         GetGesturePtr(0)->type == WebInputEvent::GestureScrollUpdate ||
+         GetGesturePtr(0)->type == WebInputEvent::GestureScrollEnd)) {
+      switch (GetGesturePtr(0)->type) {
+        case WebInputEvent::GestureScrollBegin:
+          return VrGesture(
+              kDefaultGestureScroll,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+              GetGesturePtr(0)->displacement.x * kDisplacementScaleFactor,
+              GetGesturePtr(0)->displacement.y * kDisplacementScaleFactor,
+              WebInputEvent::GestureScrollBegin, Orientation());
+        case WebInputEvent::GestureScrollUpdate:
+          return VrGesture(
+              kDefaultGestureScroll,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+              GetGesturePtr(0)->displacement.x * kDisplacementScaleFactor,
+              GetGesturePtr(0)->displacement.y * kDisplacementScaleFactor,
+              WebInputEvent::GestureScrollUpdate, Orientation());
+        case WebInputEvent::GestureScrollEnd:
+          return VrGesture(
+              kDefaultGestureScroll,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+              gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos, 0, 0,
+              WebInputEvent::GestureScrollEnd, Orientation());
+        default:
+          LOG(ERROR) << "Unknown Gesture";
+          return VrGesture();
+      }
+    }
+
+    if (IsButtonDown(gvr::kControllerButtonClick)) {
+      return VrGesture(
+          kDefaultGestureButtonsChange,
+          gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+          gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos, 1, 0,
+          Orientation());
+    }
+    return VrGesture(kDefaultGestureAngularMove,
+                     gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+                     gvr::GvrApi::GetTimePointNow().monotonic_system_time_nanos,
+                     Orientation());
+  }
+  return VrGesture();
+}
+
+void VrController::UpdateGestureFromTouchInfo() {
+  // Clear the gesture list.
+  gesture_list_.clear();
+
+  switch (state_) {
+    // User has not put finger on touch pad.
+    case WAITING:
+      HandleWaitingState();
+      break;
+    // User has not started a gesture (by moving out of slop).
+    case TOUCHING:
+      HandleDetectingState();
+      break;
+    // User is scrolling on touchpad
+    case SCROLLING:
+      HandleScrollingState();
+      break;
+    default:
+      LOG(ERROR) << "Wrong gesture detector state: " << state_;
+      break;
+  }
+}
+
+const VrGesture* VrController::GetGesturePtr(const size_t index) {
+  CHECK(index < gesture_list_.size()) << "The gesture index exceeds the"
+                                         "size of gesture list.";
+  return const_cast<VrGesture*>(&gesture_list_[index]);
+}
+
+void VrController::Update(const gvr_controller_state* controller_state) {
+  // Update touch information.
+  CHECK(touch_info_ != nullptr) << "touch_info_ not initialized properly.";
+  touch_info_->touch_up = gvr_controller_state_get_touch_up(controller_state);
+  touch_info_->touch_down =
+      gvr_controller_state_get_touch_down(controller_state);
+  touch_info_->is_touching = gvr_controller_state_is_touching(controller_state);
+  touch_info_->touch_point.position.x =
+      gvr_controller_state_get_touch_pos(controller_state).x;
+  touch_info_->touch_point.position.y =
+      gvr_controller_state_get_touch_pos(controller_state).y;
+  Vector::ClampTouchpadPosition(&(touch_info_->touch_point.position));
+  touch_info_->touch_point.timestamp =
+      gvr_controller_state_get_last_touch_timestamp(controller_state);
+
+  UpdateGestureFromTouchInfo();
+}
+
+void VrController::HandleWaitingState() {
+  // User puts finger on touch pad (or when the touch down for current gesture
+  // is missed, initiate gesture from current touch point).
+  if (touch_info_->touch_down || touch_info_->is_touching) {
+    // update initial touchpoint
+    *init_touch_point_ = touch_info_->touch_point;
+    // update current touchpoint
+    *cur_touch_point_ = touch_info_->touch_point;
+    state_ = TOUCHING;
+  }
+}
+
+void VrController::HandleDetectingState() {
+  // User lifts up finger from touch pad.
+  if (touch_info_->touch_up || !(touch_info_->is_touching)) {
+    Reset();
+    return;
+  }
+
+  // Touch position is changed and the touch point moves outside of slop.
+  if (UpdateCurrentTouchpoint() && touch_info_->is_touching &&
+      !InSlop(touch_info_->touch_point.position)) {
+    state_ = SCROLLING;
+    VrGesture gesture;
+    gesture.type = WebInputEvent::GestureScrollBegin;
+    UpdateGesture(&gesture);
+    gesture_list_.push_back(gesture);
+  }
+}
+
+void VrController::HandleScrollingState() {
+  // Update current touch point.
+  bool touch_position_changed = UpdateCurrentTouchpoint();
+  if (touch_info_->touch_up || !(touch_info_->is_touching)) {  // gesture ends
+    VrGesture scroll_end;
+    scroll_end.type = WebInputEvent::GestureScrollEnd;
+    UpdateGesture(&scroll_end);
+    gesture_list_.push_back(scroll_end);
+
+    Reset();
+  } else if (touch_position_changed) {  // User continues scrolling and there is
+                                        // a change in touch position.
+    VrGesture scroll_update;
+    scroll_update.type = WebInputEvent::GestureScrollUpdate;
+    UpdateGesture(&scroll_update);
+    gesture_list_.push_back(scroll_update);
+  }
+}
+
+bool VrController::InSlop(const gvr::Vec2f touch_position) {
+  return (std::abs(touch_position.x - init_touch_point_->position.x) <
+          kSlopHorizontal) &&
+         (std::abs(touch_position.y - init_touch_point_->position.y) <
+          kSlopVertical);
+}
+
+void VrController::Reset() {
+  // Reset state.
+  state_ = WAITING;
+
+  // Reset the pointers.
+  prev_touch_point_.reset(new TouchPoint);
+  cur_touch_point_.reset(new TouchPoint);
+  init_touch_point_.reset(new TouchPoint);
+  touch_info_.reset(new TouchInfo);
+  Vector::VectSetZero(&overall_velocity_);
+}
+
+void VrController::UpdateGesture(VrGesture* gesture) {
+  if (!gesture)
+    LOG(ERROR) << "The gesture pointer is not initiated properly.";
+  gesture->velocity = overall_velocity_;
+  gesture->displacement = Vector::VectSubtract(cur_touch_point_->position,
+                                               prev_touch_point_->position);
+}
+
+bool VrController::UpdateCurrentTouchpoint() {
+  if (touch_info_->is_touching || touch_info_->touch_up) {
+    // Update the touch point when the touch position has changed.
+    if (!Vector::VectEqual(cur_touch_point_->position,
+                           touch_info_->touch_point.position)) {
+      prev_touch_point_.swap(cur_touch_point_);
+      *cur_touch_point_ = touch_info_->touch_point;
+
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace vr_shell